Recentemente, configuramos a integração / implantação / entrega contínua de um nodejs webapp no Google App Engine. O servidor de CI (GitLabCI) executa instalação, compilação, testes e implantação de dependências para integração / produto, dependendo da filial (desenvolvimento / mestre).

No dia de hoje, os únicos erros que enfrentamos foram durante a etapa de dependências e, portanto, não nos importamos muito com isso. Mas ontem (21/10/16), houve uma interrupção de DNS em larga escala e o pipeline falhou no meio da etapa de implantação,quebrando o prod. Basta executar novamente o pipeline, mas o problema pode se reproduzir a qualquer momento.

Minhas perguntas são:

Como podemos lidar com esse tipo de problema de rede, no processo de implantação contínua?A implantação contínua no Google App Engine é realmente uma boa ideia?Em caso afirmativo, qual é o método de implantação do App Engine? Não encontrei nenhum documento relevante sobre isso ...

No momento, temos apenas duas versões "dev" e "prod" que são atualizadas após as confirmações, mas em momentos aleatórios eu pude observar comportamentos estranhos.

Qualquer resposta / sugestão / feedback é muito bem-vindo!

Exemplo de stacktrace referente aos problemas de rede de que estou falando:

DEBUG: Error sending result: 'MetadataServerException(HTTPError(),)'. Reason: 'PicklingError("Can't pickle <type 'cStringIO.StringO'>: attribute lookup cStringIO.StringO failed",)'
Traceback (most recent call last):
  File "/google-cloud-sdk/lib/googlecloudsdk/calliope/cli.py", line 733, in Execute
    resources = args.calliope_command.Run(cli=self, args=args)
  File "/google-cloud-sdk/lib/googlecloudsdk/calliope/backend.py", line 1630, in Run
    resources = command_instance.Run(args)
  File "/google-cloud-sdk/lib/surface/app/deploy.py", line 53, in Run
    return deploy_util.RunDeploy(self, args)
  File "/google-cloud-sdk/lib/googlecloudsdk/command_lib/app/deploy_util.py", line 387, in RunDeploy
    all_services)
  File "/google-cloud-sdk/lib/googlecloudsdk/command_lib/app/deploy_util.py", line 247, in Deploy
    manifest = _UploadFiles(service, code_bucket_ref)
  File "/google-cloud-sdk/lib/googlecloudsdk/command_lib/app/deploy_util.py", line 115, in _UploadFiles
    service, code_bucket_ref)
  File "/google-cloud-sdk/lib/googlecloudsdk/api_lib/app/deploy_app_command_util.py", line 277, in CopyFilesToCodeBucketNoGsUtil
    _UploadFiles(files_to_upload, bucket_ref)
  File "/google-cloud-sdk/lib/googlecloudsdk/api_lib/app/deploy_app_command_util.py", line 219, in _UploadFiles
    results = pool.map(_UploadFile, tasks)
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 251, in map
    return self.map_async(func, iterable, chunksize).get()
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 558, in get
    raise self._value
MaybeEncodingError: Error sending result: 'MetadataServerException(HTTPError(),)'. Reason: 'PicklingError("Can't pickle <type 'cStringIO.StringO'>: attribute lookup cStringIO.StringO failed",)'
DEBUG: Exception captured in Error
Traceback (most recent call last):
  File "/google-cloud-sdk/lib/googlecloudsdk/core/metrics.py", line 411, in Wrapper
    return func(*args, **kwds)
TypeError: Error() takes exactly 3 arguments (1 given)
ERROR: gcloud crashed (MaybeEncodingError): Error sending result: 'MetadataServerException(HTTPError(),)'. Reason: 'PicklingError("Can't pickle <type 'cStringIO.StringO'>: attribute lookup cStringIO.StringO failed",)'
Traceback (most recent call last):
  File "/google-cloud-sdk/lib/gcloud.py", line 65, in <module>
    main()
  File "/google-cloud-sdk/lib/gcloud.py", line 61, in main
    sys.exit(googlecloudsdk.gcloud_main.main())
  File "/google-cloud-sdk/lib/googlecloudsdk/gcloud_main.py", line 145, in main
    crash_handling.HandleGcloudCrash(err)
  File "/google-cloud-sdk/lib/googlecloudsdk/command_lib/crash_handling.py", line 107, in HandleGcloudCrash
    _ReportError(err)
  File "/google-cloud-sdk/lib/googlecloudsdk/command_lib/crash_handling.py", line 86, in _ReportError
    util.ErrorReporting().ReportEvent(error_message=stacktrace,
  File "/google-cloud-sdk/lib/googlecloudsdk/api_lib/error_reporting/util.py", line 28, in __init__
    self._API_NAME, self._API_VERSION)
  File "/google-cloud-sdk/lib/googlecloudsdk/core/apis.py", line 254, in GetClientInstance
    http_client = http.Http()
  File "/google-cloud-sdk/lib/googlecloudsdk/core/credentials/http.py", line 60, in Http
    creds = store.Load()
  File "/google-cloud-sdk/lib/googlecloudsdk/core/credentials/store.py", line 282, in Load
    if account in c_gce.Metadata().Accounts():
  File "/google-cloud-sdk/lib/googlecloudsdk/core/credentials/gce.py", line 122, in Accounts
    gce_read.GOOGLE_GCE_METADATA_ACCOUNTS_URI + '/')
  File "/google-cloud-sdk/lib/googlecloudsdk/core/util/retry.py", line 160, in TryFunc
    return func(*args, **kwargs), None
  File "/google-cloud-sdk/lib/googlecloudsdk/core/credentials/gce.py", line 45, in _ReadNoProxyWithCleanFailures
    raise MetadataServerException(e)
googlecloudsdk.core.credentials.gce.MetadataServerException: HTTP Error 503: Service Unavailable
DEBUG: Uploading [/builds/apps/webapp/lib/jinja2/defaults.pyc] to [151c77b4e5bdd2c38b6a2bf914fffa3a6ffa71a6]
INFO: Uploading [/builds/apps/webapp/lib/jinja2/defaults.pyc] to [151c77b4e5bdd2c38b6a2bf914fffa3a6ffa71a6]
INFO: Refreshing access_token